Background and Objective: JWH133 is known to have cannabinoid-2 (CB2) receptor agonist properties. Celecoxib, a selective cyclooxygenase-2 (COX-2) inhibitor, is also known to have antinociceptive properties. Endocannabinoids produce analgesia possibly through cyclooxygenase (COX) pathway. The aim of the present work was: to study the effect of celecoxib on JWH133 induced antinociception and to compare the effects of two different dose ranges of celecoxib (mg/kg and nano g/kg) on the JWH133 antiniciceptive effect. Materials and Methods: We have studied the possible interaction of administration of mg/kg (50-200 mg/kg) and Ultra-Low Dose (ULD) (25 and 50 ng/kg) of celecoxib on the antinociceptive effect of intraperitoneal (i.p.) injection of JWH133 using formalin test in mice. Results: JWH133 (0.01, 0.1 and 1 mg/kg) induced antinociceptive effect just in phase I of the formalin test. Celecoxib (50-200 mg/kg) and its ULD (25 and 50 ng/kg) attenuated and potentiated, JWH133 induced antinociception, respectively. Conclusions: It is concluded that JWH-133 induced antinociception is modulated by celecoxib and mg/kg doses of celecoxib showed opposite effects compare to its ultra-low doses.